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Refactor syzygy code in search

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Move to SF coding style.

Also skip calculating piece count in search()
when TB are not found (!TBCardinality)

No functional change.
This commit is contained in:
Marco Costalba 2014-11-30 08:38:46 +01:00 • committed by Joona Kiiski
parent 35c1ccef39
commit c30eb4c9c9
1 changed files with 47 additions and 56 deletions
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59
src/search.cpp
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@ -188,13 +188,24 @@ template uint64_t Search::perft<true>(Position& pos, Depth depth);
void Search::think() { void Search::think() {
TimeMgr.init(Limits, RootPos.game_ply(), RootPos.side_to_move()); TimeMgr.init(Limits, RootPos.game_ply(), RootPos.side_to_move());
TBHits = TBCardinality = 0;
RootInTB = false;
int cf = Options["Contempt"] * PawnValueEg / 100; // From centipawns int cf = Options["Contempt"] * PawnValueEg / 100; // From centipawns
DrawValue[ RootPos.side_to_move()] = VALUE_DRAW - Value(cf); DrawValue[ RootPos.side_to_move()] = VALUE_DRAW - Value(cf);
DrawValue[~RootPos.side_to_move()] = VALUE_DRAW + Value(cf); DrawValue[~RootPos.side_to_move()] = VALUE_DRAW + Value(cf);
TBHits = 0;
RootInTB = false;
TBProbeDepth = Options["SyzygyProbeDepth"] * ONE_PLY;
TB50MoveRule = Options["Syzygy50MoveRule"];
TBCardinality = Options["SyzygyProbeLimit"];
// Skip TB probing when no TB found: !TBLargest -> !TBCardinality
if (TBCardinality > Tablebases::TBLargest)
{
TBCardinality = Tablebases::TBLargest;
TBProbeDepth = DEPTH_ZERO;
}
if (RootMoves.empty()) if (RootMoves.empty())
{ {
RootMoves.push_back(MOVE_NONE); RootMoves.push_back(MOVE_NONE);
@ -204,36 +215,16 @@ void Search::think() {
} }
else else
{ {
// Check Tablebases at root if (TBCardinality >= RootPos.count<ALL_PIECES>(WHITE)
int piecesCnt = RootPos.count<ALL_PIECES>(WHITE) + RootPos.count<ALL_PIECES>(BLACK); + RootPos.count<ALL_PIECES>(BLACK))
TBCardinality = Options["SyzygyProbeLimit"];
TBProbeDepth = Options["SyzygyProbeDepth"] * ONE_PLY;
if (TBCardinality > Tablebases::TBLargest)
{ {
TBCardinality = Tablebases::TBLargest;
TBProbeDepth = 0 * ONE_PLY;
}
TB50MoveRule = Options["Syzygy50MoveRule"];
if (piecesCnt <= TBCardinality)
{
TBHits = RootMoves.size();
// If the current root position is in the tablebases then RootMoves // If the current root position is in the tablebases then RootMoves
// contains only moves that preserve the draw or win. // contains only moves that preserve the draw or win.
RootInTB = Tablebases::root_probe(RootPos, TBScore); RootInTB = Tablebases::root_probe(RootPos, TBScore);
if (RootInTB) if (RootInTB)
{
TBCardinality = 0; // Do not probe tablebases during the search TBCardinality = 0; // Do not probe tablebases during the search
// It might be a good idea to mangle the hash key (xor it
// with a fixed value) in order to "clear" the hash table of
// the results of previous probes. However, that would have to
// be done from within the Position class, so we skip it for now.
// Optional: decrease target time.
}
else // If DTZ tables are missing, use WDL tables as a fallback else // If DTZ tables are missing, use WDL tables as a fallback
{ {
// Filter out moves that do not preserve a draw or win // Filter out moves that do not preserve a draw or win
@ -244,15 +235,14 @@ void Search::think() {
TBCardinality = 0; TBCardinality = 0;
} }
if (!RootInTB) if (RootInTB)
{
TBHits = 0;
}
else if (!TB50MoveRule)
{ {
TBHits = RootMoves.size();
if (!TB50MoveRule)
TBScore = TBScore > VALUE_DRAW ? VALUE_MATE - MAX_PLY - 1 TBScore = TBScore > VALUE_DRAW ? VALUE_MATE - MAX_PLY - 1
: TBScore < VALUE_DRAW ? -VALUE_MATE + MAX_PLY + 1 : TBScore < VALUE_DRAW ? -VALUE_MATE + MAX_PLY + 1
: TBScore; : VALUE_DRAW;
} }
} }
@ -470,7 +460,6 @@ namespace {
bool inCheck, givesCheck, singularExtensionNode, improving; bool inCheck, givesCheck, singularExtensionNode, improving;
bool captureOrPromotion, dangerous, doFullDepthSearch; bool captureOrPromotion, dangerous, doFullDepthSearch;
int moveCount, quietCount; int moveCount, quietCount;
int piecesCnt;
// Step 1. Initialize node // Step 1. Initialize node
Thread* thisThread = pos.this_thread(); Thread* thisThread = pos.this_thread();
@ -549,10 +538,11 @@ namespace {
} }
// Step 4a. Tablebase probe // Step 4a. Tablebase probe
piecesCnt = pos.count<ALL_PIECES>(WHITE) + pos.count<ALL_PIECES>(BLACK); if (!RootNode && TBCardinality)
{
int piecesCnt = pos.count<ALL_PIECES>(WHITE) + pos.count<ALL_PIECES>(BLACK);
if ( !RootNode if ( piecesCnt <= TBCardinality
&& piecesCnt <= TBCardinality
&& (piecesCnt < TBCardinality || depth >= TBProbeDepth) && (piecesCnt < TBCardinality || depth >= TBProbeDepth)
&& pos.rule50_count() == 0) && pos.rule50_count() == 0)
{ {
@ -580,6 +570,7 @@ namespace {
return value; return value;
} }
} }
}
// Step 5. Evaluate the position statically and update parent's gain statistics // Step 5. Evaluate the position statically and update parent's gain statistics
if (inCheck) if (inCheck)